Impact of dust contamination on our SZ measurements. Three cases are shown: a 6-band MMF (all Planck HFI frequencies) with no explicit allowance for a dust contribution (green triangles), a 3-band MMF also with no explicit dust modelling (red diamonds); and a modified 6-band MMF that includes an amplitude fit to a fiducial dust spectrum (blue crosses). The error bars include measurement uncertainties only. For stellar masses where we clearly detect the signal (i.e., at log ₁₀M_∗/M_⊙ > 11.25), the three measurements agree, indicating that dust emission does not significantly affect those measurements. At lower masses the 3-band results are consistent with the 6-band results when dust is explicitly included in the modelling, but not otherwise.